1. Field of the Invention
The present invention relates to the field of liquid crystal display technology, and in particular to a liquid crystal display device.
2. The Related Arts
Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus of wide applications, such as liquid crystal televisions, mobile phones, personal digital assistants (PDAs), digital cameras, computer monitors, and notebook computer screens.
Most of the currently available liquid crystal displays are backlighting liquid crystal displays, which comprise an enclosure, a liquid crystal panel arranged in the enclosure, and a backlight module mounted in the enclosure. The liquid crystal panel itself does not emit light and light must be supplied from the backlight module to the liquid crystal panel in order to normally display images
FIG. 1 shows a schematic view of a conventional liquid crystal display device. The structure of a conventional liquid crystal panel 100 is made up of a color filter (CF) substrate 110, a thin-film transistor (TFT) array substrate 130, and a liquid crystal layer filled between the two substrates and the principle of operation is that a driving voltage is applied to the CF substrate 110 and the array substrate 130 to control rotation of the liquid crystal molecules of the liquid crystal layer in order to control the amount of output light for refracting out light emitting from a backlight module 300 to generate images. The CF substrate 100 has an upper surface on which an upper polarizer film 150 is attached and the CF substrate 100 has a lower surface on which color resist is arranged by taking pixels as units. The array substrate 130 has a lower surface on which a lower polarizer film 170 that is normal to the upper polarizer film 150 in directions of axes thereof. The array substrate 130 has an upper surface on which TFT switches are provided for charging/discharging of the pixels. Formed atop the TFT switches is an indium tin oxide (ITO) electrode that controls the liquid crystal layer. The ITO electrode is arranged in a pattern that can be designed as an electrode pattern that is fit for a twisted nematic (TN) mode, or as a pattern that is fit for one-domain, two-domain, four-domain, or eight-domain vertical alignment (VA) mode, or a pattern that is fit for one-domain, two-domain, or four-domain in-plane switching (IPS) mode.
A conventional backlight module 300 comprises a backlight source 310, a light guide plate 330, a bottom reflector plate 350, and an optic film assembly 370. The backlight source 310 can be a light-emitting diode (LED), a cold cathode fluorescent lamp (CCFL), or a hot cathode fluorescent lamp (HCFL). The optic film assembly 370 comprises a diffuser film, a bright enhancement film, and a protection film.
The conventional liquid crystal television produces often adopt a driving method of a VA mode solution or an IPS mode solution in order to expand the view angle of displaying. The VA mode has advantages of high yield rate and high throughput; however, to reduce color shift for displaying at large view angles, the ITO electrode must adopt the eight-domain solution to improve color deviation at large view angles. Using ITO electrode of the eight-domain pattern would lead to a reduction of the yield rate of a manufacturing process, a reduction of the aperture ratio, a reduction of liquid crystal performance, and a reduction of light transmittance, and thus the cost of the backlight module is indirectly increased. On the other hand, using a two-domain or one-domain VA mode solution allows for a signification increase of light transmittance, but color deviation becomes apparently severe at large view angles.
Further, since a display panel of a liquid crystal television needs a large view angle for watching and view angel brightness must satisfy the view angle specification of ½ brightness or ⅓ brightness. The optic film assembly of the backlight module needs to have a relatively large light-exit view angle. Since the light transmittance of the liquid crystal panel at a large view angle is reduced, the light extraction performance of the backlight module gets deteriorated and the large view angle color deviation issue of the liquid crystal panel is made apparently identifiable.